Program Director/Principal Investigator (Last, First, Middle): Gantz, Bruce J. PROJECT SUMMARY ? CORE B Core B's primary responsibilities are to accrue a subject population; provide the clinical service for these subjects; maintain a cochlear implant (CI) research registry; monitor postoperative residual hearing; and obtain audiologic and speech perception outcome measures that will be used in the research projects. Core B will also provide the technical and statistical support for all investigators. The four research projects are highly interdependent and interrelated. Each project depends on data generated by the others to address their specific aims, using similar subject populations to address the Iowa Cochlear Implant Clinical Research Center's (ICICRC) overall goals. Described here are (1) extensive preoperative evaluations required for subject accrual; (2) specific populations to be studied; (3) CIs to be used; (4) basic audiologic and speech perception outcome measures of performance that will be obtained from subjects; and (5) the time-line of subject involvement. The overall statistical design, data management and technical support are also discussed. The individual projects describe the specific research questions and how each project is interactive and dependent on the others.